The sum paid for the use of money, hence interest; not, as in the modern sense, exorbitant interest. The Jews were forbidden to exact usury (Leviticus 25:36,37), only, however, in their dealings with each other (Deuteronomy 23:19,20). The violation of this law was viewed as a great crime (Psalms 15:5; Proverbs 28:8; Jeremiah 15:10). After the Return, and later, this law was much neglected (Nehemiah 5:7,10).
These dictionary topics are from M.G. Easton M.A., D.D., Illustrated Bible Dictionary, Third Edition, published by Thomas Nelson, 1897. Public Domain, copy freely.
Easton, Matthew George. "Entry for 'Usury'". "Easton's Bible Dictionary".